Low oil pressure warning

[jimmy156]

Hello all,

Under hard cornering/acceleration (coming off a roundabout for example) i have twice has the "low oil pressue - do not continue your journey engine damage possible" warning flash up for a few seconds and then clear away again.

After the first time i stuck just over a litre of oil in and assumed that was the issue, but it has happened again since and the oil level is currently fine.

On phoning the garage they said that it would just be because of the hard cornering and that there isn't necessarily a fault. Whilst I can totally see the argument for this with what the oil in the sump will be doing under those conditions, this is not a problem i have had before and i don't think i can just continue to ignore the warning messages when they occur.

I have it booked in anyway, but has anyone come across this before and if so; what was the problem / solution?

ETA: Car is 2011 R56 Cooper S with N18 engine.

TIA,
Jimmy

[Rockster]

jimmy156 said:

Hello all,

Under hard cornering/acceleration (coming off a roundabout for example) i have twice has the "low oil pressue - do not continue your journey engine damage possible" warning flash up for a few seconds and then clear away again.

After the first time i stuck just over a litre of oil in and assumed that was the issue, but it has happened again since and the oil level is currently fine.

On phoning the garage they said that it would just be because of the hard cornering and that there isn't necessarily a fault. Whilst I can totally see the argument for this with what the oil in the sump will be doing under those conditions, this is not a problem i have had before and i don't think i can just continue to ignore the warning messages when they occur.

I have it booked in anyway, but has anyone come across this before and if so; what was the problem / solution?

ETA: Car is 2011 R56 Cooper S with N18 engine.

TIA,
Jimmy

Just dumping in a liter of oil without confirming the oil level first is a bit well, odd. Maybe the oil level was ok to begin with? Or maybe, just maybe, the level is down more than a liter's worth?

Have you fitted sticky tires? In some cases some cars can suffer oiling problems with sticky/racing tires fitted because of increased cornering speeds/braking g-forces.

Another possible explanation is the oil is old, has high miles on it, or has the wrong kind of miles on it -- short trips -- and is heavily contaminated. In this condition the oil foams more and in some conditions under hard cornering and at high RPMs this can allow oil that has not had time to shed its content of air to the oil pump intake and oil with some air is circulated. This can result in a momentary drop in oil pressure. In some cases with engines that have hydraulic valve lifters the lifters partially collapse due to the air in the oil and this affects valve lift and timing. A sign this is happening -- on a dyno at least -- is at high RPMs -- near red line -- a drop in oil pressure concurrent with a drop off in HP.

The "wrong" oil can also contribute to low oil pressure if the oil is not able to withstand/tolerate extreme operating conditions like elevated oil temperature with high RPMs.

If the oil is fresh, the right oil, the oil level correct, and the car is not fitted with sticky tires it could be a problem with the oil pan baffling. Normally the baffling is designed to ensure a good supply of oil under/around the oil pump intake under all operating conditions. This is accomplished by baffles that open inward and let oil in but on the other side if any oil in the enclosed area wants to flow out it can't because the baffle on that doesn't open out only in.

If a baffle has failed, become partially stuck open, has suffered some kind of mechanical problem, under some high g conditions -- taking a roundabout at high speed -- this can let oil flow away from the oil pick up.

If there are no other explanations then it might make sense to remove the oil pan and inspect the oil pan baffles for any signs of any problems. At the same time the oil pump intake tube can be checked to make sure it is secure and has no leaks. If the pump intake tube can move about to follow the oil around the bottom of the pan under changes in g force direction that feature wants to be checked to make sure it works properly.

It may be worth considering installing a better/deeper/higher capacity oil pan too one that provides more oil and an extra margin of safety the oil pump pick up will never get less than 100% liquid oil under any high g forces. This increase in oil capacity also addresses in some cases under high g forces oil can "puddle" or "pool" in the engine and this lowers the oil level in the pan.

(I never experienced it but with my Boxster it had an oil scavenge pump under each camshaft cover. One pump was at the front of the camshaft cover on one bank while on the other bank the oil scavenge pump was at the back of the camshaft cover. Under a high speed corner (I don't recall the direction) with hard braking and even worse if the corner was on a downhill section g force would let oil pile up under the camshaft cover away from the oil scavenge pump to the point the oil level in the oil sump would drop and the engine could experience low oil pressure and supply. This is one reason why Porsche did not condone the use of racing/track tires on the car.)

[jimmy156]

Sorry, perhaps I should have been more explicit.

After warning 1, I checked then oil and it was low so I topped it up to near the high point on the dipstick.

After warning 2 I checked again and the oil was still at a good level.

The oil is as per the MINi specification, as is the frequency of oil changes. The car does almost only longer runs, my commute is about 40mi each way.

Thanks for all the other info, very helpful